Coral reefs, the storehouses of much of the world’s marine biodiversity, and the source of many socioeconomic benefits, are in decline worldwide. The causes of the ‘coral reef crisis’ are complex but there is general agreement that two broad categories of stress are involved: global-scale climatic changes induced by production of greenhouse gases, and local-scale impacts. The major feature of climate change affecting coral reefs is rising sea temperature, which has caused widespread coral bleaching and is implicated in increased occurrence of coral diseases and reduced rates of calcification. Local impacts on coral reefs stem from natural phenomena, such as storms, and from human populations in coastal areas, which are large and growing. The local human impacts include increased nutrient and sediment loads, habitat modification, destructive fishing and chronic overfishing. The losses of biodiversity, and lost opportunities for coastal communities to earn sustainable incomes from coral reefs, that can result from local human impacts are illustrated by blast, cyanide and muro-ami fishing. These destructive methods reduce the physical complexity and live coral cover of reefs and, because degraded reefs support fewer fish, ultimately remove the basis for long-term fish productivity. In Indonesia alone, blast fishing is estimated to have resulted in a loss of US$3.8 billion over 25 years.